Method of making alcohol-soluble complexes of aluminum



United States Patent 3,523,130 METHOD OF MAKING ALCOHOL-SOLUBLECOMPLEXES OF ALUMINUM John L. Jones, North Plainfield, and Andrew M.Rubino,

New Providence, N.J., assignors to Armour Pharmaceutical Company,Chicago, 11]., a corporation of Delaware N 0 Drawing.Continuation-impart of apphcation Ser. No. 603,133, Dec. 20, 1966, whichis a COIltlIlllZltlOll-lIl-pfil't of application Ser. No. 472,684, July16, 1965. This application Oct. 23, 1968, Ser. No. 770,104

The portion of the term of the patent subsequent to Jan. 7, 1986, hasbeen disclaimer] Int. Cl. C07f /06 US. Cl. 260448 9 Claims ABSTRACT OFTHE DISCLOSURE The method of preparing an inorganic-organic coordinatedcomplex of aluminum comprising refluxing for from 2 to 6 hours atatmospheric pressure an aqueous solution of basic aluminum chloridehaving the approximate formulation A1 (OH) Cl, with the atomic ratio ofaluminum to chlorine being between 1.88 and 1.95 to 1, reacting at atemperature of 50 C. to 120 C. said aluminum compound with a polyhydroxycompound having at least 2 carbon atoms, each of which is linked to ahydroxy group, to form a mixture, and then removing the water from saidlast-mentioned mixture by spray drying at atmospheric pressure to Obtaina product having a Water content of from about 1.0 to about 10 weightpercent determined by Karl Fischer analysis.

The present invention is directed to a method of making alcohol solublecomplexes of aluminum. It is a continuation-in-part of United Statespatent application Ser. No. 603,133 filed Dec. 20, 1966 entitled: Methodof Making Alcohol Soluble Complexes of Aluminum and PreparationsEmploying the Complexes, now United States Letters Patent 3,420,932issued I an. 7, 1969. Such patent application Ser. No. 603,133 is acontinuation-in part of our patent application Ser. No. 472,684 filedJuly 16, 1965, now abandoned. The text of patent application Ser. No.603,133 is incorporated herein by reference.

Patent application Ser. No. 603,133 is directed to a method of preparingan inorganic-organic coordinated complex of aluminum by mixing anaqueous solution of an aluminum-containing material, such as aluminumbasic chloride, with a polyhydroxy compound, having at least 2 carbonatoms, each of which is linked to a hydroxy group, to form a mixture,followed by the heating of said mixture, and subsequent drying to yieldthe complex which has a water content of from about 1.0 to about 10weight percent determined by Karl Fischer analysis.

The complex derived by the method of patent application Ser. No. 603,133has great utility in anhydrous alcohol aerosol formulations used asantiperspirants. Thus, the complexes derived by the method of patent application Ser. No. 603,133 are both reasonably soluble in anhydrousalcohol, and reasonably compatible with the available aerosolpropellants, such as the halogenated (fluoro chloro) hydrocarbons. Whilethese complexes are satisfactory for usage in aerosol containers, yet ithas proved desirable to achieve complexes which are more soluble inanhydrous alcohol and more compatible with the propellant. Increasedsolubility in anhydrous alcohol enables more concentrated aerosolformulations to be prepared. The use of anhydrous alcohol enables muchof the extreme corrosion induced by aqueous media to the metal valvesand containers for the aerosol preparation to be avoided.

Maximum compatibility with aerosol dispenser propellants is mostdesirable so as to minimize valve clogging and other impairment of theaerosol dispenser function.

This invention has as an object the provision of alcohol solublecomplexes of aluminum which possess both increased solubility inanhydrous alcohol, and improved compatibility with aerosol propellants.

This invention has as a further object the provision of the aforesaidalcohol soluble complexes of aluminum.

Other objects will appear hereinafter.

We have discovered that if the basic aluminum chloride used to preparethe alcohol soluble complex is refluxed for between 2 to 6 hours, andpreferably about 4 hours refluxing, within the temperature range of toC. prior to the complex formation with the polyhydroxy compound, and itsatomic aluminum to atomic chlorine ratio adjusted to between 1.88 to1.95 to 1, and preferably about 1.9 to 1, a more soluble in anhydrousalcohol and a more compatible with aerosol propellant complex isobtained upon the removal of water by spray drying at atmosphericpressure from the complex to the level of about 1.0 to about 10 weightpercent determined by Karl Fischer analysis.

We have discovered that at least about 2 hours refluxing is needed toobtain this improvement. There does not appear to be a sharp maximumamount of time for refluxing. However, when refluxing is extended morethan about 6 hours, the cost of the process is increased without anyappreciable attendant advantage. Moreover,

wherein R is the coordinating moiety of a polyhydroxy compound having acarbon chain in which at least two carbon atoms link a hydroxyl group tosaid chain; y is from 2 to 6 and need not be a positive integer; p isthe number of mols of the polyhydroxy compound and need not be apositive integer; z is the number of available coordination positionsoccupied by R; n is 1 to 4 but need not be a positive integer; and x is1, with we being from The aforesaid formula should not be interpreted asmeaning that only water is displaced by R, since R could also displaceany OH which are bound to the aluminum atoms. This could also occur,inter alia, by virtue of the condensation of the polyol hydroxy groupswith the hydroxy groups bonded to the aluminum atoms. Where more thanone hydroxy group of a given polyol molecule condenses with the hydroxygroups bonded to aluminum,

chelate structures may be formed. Still other mechanisms can bepostulated.

The optimum coordination compounds (complexes) of the present inventionhave the formula:

2( 2 )o.z-1.1( )4.9-5.1( )0.9-1.1( Propylene y lomrs In the aboveformula, the 1,2-propylene glycol may be present in the complex in anumber of ways, namely with both carbinol hydrogen atoms being lost bycondensation or neutralization, or with only one carbinol hydrogen atombeing lost by condensation or neutralization, or with both hydroxygroups remaining intact and coordinated and/ or chelated to one of thealuminum atoms.

Suitable polyhydroxy compounds for use in the practice of the presentinvention include: propylene glycol; 1,1,1- trimethylol propane;1,3-butylene glycol (1,3-butanediol); glycerine (1,2,3-trihydroxypropane); 2-methyl-2,4- pentane-diol; neopentyl glycol(2,2-dimethyl-l,3-dihydroxy pentane); polyethylene glycol (mol wt.=400);Polyglycol 20O (a Dow material having an ethereal linkage betweenpropylene oxide and ethylene and condensed with glycerine in which eachchain has a terminal hydroxy group (mol wt.=2700); p-xylene or, a=-diol;and polyepichlorohydrin; butyne-1,4-diol; 2-ethyl-1,3-hexanediol; andpolypropylene glycol (av. mol. wt.=400)).

The preferred polyhydroxy compound is 1,2-propylene glycol. In addition,we have obtained superior products with 1,3-butane diol, and withtrimethylolpropane.

In one embodiment of the present invention, we are able to modifyaluminum chlorohydroxide to obtain a coordination compound of superiorproperties.

Specifically, we prepared an aqueous solution of aluminumchlorohydroxide ranging from 43-50 percent solids and to this solution,refluxed for from 2 to 6 hours at atmospheric pressure, added from about53 to about 100% of 1,2-propylene glycol (based on the aluminumchlorohydroxide solids content), reacted the resultant mixture at 50 to120 C. and spray dried the mixture at atmospheric pressure to a producthaving a water content of from about 1.0 to about 10 weight percentdetermined by the Karl Fischer assay method.

The reaction between the aluminum chlorohydroxide and the polyhydroxycompound should be effected at a temperature within the range of 50 to120 C. Preferably, the reaction temperature should be of the order of 80to 110 C. We have found that a temperature range of 90 to 105 C. isoptimum. A reaction can be effected in the presence of agitation, suchas stirring or other conventional mixing procedures. The time of thereaction is temperature dependent, and operational times may bedetermined for any specific concentrations and specific startingmaterials by routine testing within the skill of a worker in the art.Generally, a duration of the order of from a few minutes to severalhours constitutes adequate reaction time. In addition to the reactiontime being temperature dependent, it is also dependent upon the extentof agitation applied to the mixture.

The coordination compounds of the present invention are dried by spraydrying to a product containing between about 1 and 10 weight percent ofmoisture as determined by the Karl Fischer assay method.

The spray drying temperatures to be used in the process of the presentinvention will vary depending on the size of the spray drier. With theBowen No. 2 7-foot diameter spray drier and larger, an inlet temperatureof 200 to 320 C. can be used with the preferred inlet temperature beingabout 225 to 270 C. An outlet temperature range of 100 C. to 160 C.should be used. For laboratory size spray driers, such as a BowenFlat-Bottom labo ratory spray drier (30-inch diameter) an inlettemperature range of the order of 90 C. to 260 C. may be used, with apreferred inlet temperature range of 150 C. to 210 C. With such smallsize spray driers, an outlet temperature within the range of 80 to 125C. may be used,

4. with the preferred outlet temperature range being between C. and C.

It has been found that the spray dried product should be cooled asrapidly as possible to a temperature of 50 C. or less.

One system, which has been proven successful, consists of an airconveying system. Product is removed from the drier waste gas streamthrough a rotary lock valve. The product at a temperature ofapproximately 100 to C. is dropped into an air stream, cooled andconveyed to a final collection point. The conveying air is ambient airthat has been cooled to less than 45 F. maximum by a refrigerationsystem. At the cold temperature, the air is saturated with water vapor.In the process of cooling the hot product, the air is naturally warmedto 7080 F with no additional water being added to the air since noadditional product drying is occurring. The resultant relative humidityof the air is less than 40%. Any ambient air temperature below 45 F. isadvantageous due to the lower relative humidity after being heated. Thetemperature of the final product is dependent upon the air flow rate. AHow rate of approximately 10% of the total drier air flow rate cools theproduct to 80 F. with a 45 F. inlet temperature. If the spray driedproduct is not cooled as rapidly as possible, then deterioration setsin, and in particular, impaired solubility in anhydrous alcohol, andreduced compatibility with aerosol propellants, such asfluorohydrocarbons results.

As above-indicated the range of water as determined by the Karl Fischerassay method in the final product should be of the order of 1 to 10weight percent. Preferably, it should be of the order of about 4 /2 to8%, with about 6 weight percent being optimum.

In all cases, an excess of polyhydroxy compound should be used toprepare the coordination compounds of the present invention, since asignificant amount of polyhydroxy compound is lost by evaporation (suchevaporated polyhydroxy compound can be recovered by condensation). Theevaporation of the polyhydroxy compound occurs during refluxing,although where spray drying forms the drying method, a major portion ofthe evaporated polyhydroxy compound is lost during spray drying. Withspray dried coordination compounds of the present invention depending onthe volatility of the polyhydroxy compound and the conditions of spraydrying, as much as 30 to 50 weight percent of the initial amount of thepolyhydroxy compound is lost on evaporation. For this reason, whereevaporation of glycol is encountered, it is necessary to start off withan excess amount of glycol, since if the stoichiometric amount of glycolis used initially, the correct ratio of glycol to aluminum will not beachieved in the final product. During spray drying, glycol and water arethe only materials being removed. Thus, for example, we can commencewith a ratio of 0.95 mol of aluminum per mol of propylene glycol and geta final product which contains a ratio of about 2 mols of aluminum permol of propylene glycol after spray drying.

The complex (that is, the dry product) produced by our method exhibitsantiperspirant properties which compare favorably by subjectiveevaluation to aluminum chlorohydroxide. This effect is believed toresult from our retention of the ionicity of the aluminum in ourcomplex.

While the exact mechanism of the reaction is not fully understood, it isbelieved to involve the displacement of free and bound water and,possibly, a displacement or condensation with hydroxy groups attached tothe aluminum ion. The hydroxy groups of the polyhydroxy compound appearto be unreactive with the chloride ion.

We have endeavored to work up a simulated aerosol medium forascertaining compatibility and solubility of our product. Since thenormal fluorocarbons used in aerosols were too volatile for practicalmeasurements, carbon tetrachloride was arbitrarily selected because ofits nonpolar similarity and nonvolatility. For convenience, 60.0 g. of a30% solution of the antiperspirant in anhydrous 5 SD-40 alcohol wastitrated with carbon tetrachloride. The ml. of CCL; required to causethe first permanent haze was called the compatibility number. Althoughit is recognized that the absolute values of carbon tetrachloride andvarious fluorocarbons would not be the same, there is a proportionalrelationship.

In the examples set forth below, the compatibility is given as thenumber of ml. of CCl.;.

The products produced by the process of the present invention have agreater compatibility and a greater solubility in respect to aerosolpropellants.

The preparation of the basic aluminum chloride in accordance with theprocess of the present invention may be illustrated as follows:

EXAMPLE A Into a 500-gallon reactor equipped with agitation and a heatexchanger was charged 2950 pounds of 24 B. A101 and 1720 pounds ofwater. After preheating, 580 pounds of aluminum powder was added in 10pound increments maintaining an average reaction temperature of about 85C. After approximately 6 hours, when nearly all of the aluminum hasdissolved, an additional 35 pounds of aluminum powder was added and thebatch filtered.

The aforesaid composition assayed 12.4% Al and 8.5% C1. The atomic ratiomay be derived from the aforesaid analysis,

atomic ratio weight of aluminum/atomic weight of aluminum weight ofchlorine/atomic weight of chlorine Into a glass-lined SOD-gallon reactorequipped with an agitator, heat exchanger and condenser was charged 3300pounds of the aforesaid solution. The temperature of the solution waselevated to 225 F. and maintained at this temperature for a period of4.0 hours.

The use of the refluxed basic aluminum chloride prepared as above tomake the complex of the present invention is set forth below.

EXAMPLE 1 To the solution derived from Example A was added 1158 poundsof propylene glycol and the mixture allowed to concentrate (Maximumtemperature of 240 F.) to about 3530 pounds or a viscosity of about 180cps. by maintaining the mixture at 225 F.

The concentrated solution was cooled and dried in a Bowen 7-foot spraydryer at an outlet temperature of 290 F. to yield 1728 pounds of alcoholsoluble solids assaying 20.2% A], 13.7% C1, 6.5% H by Karl Fischerassay, 32.8% propylene glycol, compatibility=l97 ml. 001,.

Examples 2 and 3 illustrate the comparison between basic aluminumchloride that had been refluxed in accordance with the process of thepresent invention and basic aluminum chloride that had not beenrefluxed. It is to be emphasized that Example 2 yielded a satisfactoryproduct, but that the product of Example 3 is superior.

EXAMPLE 2 2030 g. of aqueous basic aluminum chloride solution and 790 g.of U.S.P. propylene glycol were subjected to heating at 90 C. for aperiod of two hours. The concentrate was spray dried through a BowenFlat-Bottom spray dryer {30-inch diameter) at an inlet temperature of500 F. and outlet temperature of 175 F. The white powdered productassayed 20.5% A1, 13.6% C1, 7.7% H 0 and had a compatibility of 184 ml.C014. The product was rapidly soluble (5-10 minutes) in anhydrousethanol, but the solution was cloudy indicating incomplete associationbetween the components and about 0.1% decomposition of the basicaluminum halide.

6 EXAMPLE 3 To 3050 g. of a 50% basic aluminum chloride solution added60 g. of 32 B. aluminum chloride and subjected the mixture to refluxconditions (100105 C.) for a period of 4.0 hours. To the hot solutionwas added 1204 g. of U.S.P. propylene glycol, and with agitation thesolution was concentrated at 100-105 C. until a viscosity of 184 cps.was attained.

The concentrate was spray dried through a Bowen Flat- Bottom spray dryer(-inch diameter) at an inlet temperature of about 300 F. and an outlettemperature of 245 F. The product assayed 19.8% A1, 13.5% Cl, 7.1% H 0.The compatibility was 327 ml. CCl The product was rapidly soluble inanhydrous ethanol and showed virtually no decomposition.

We cannot satisfactorily explain the improved solubility in anhydrousalcohol and the improved compatibility with aerosol propellant of thepolyhydroxy complexes of the present invention. However, it is ourbelief that the refluxing in some fashion changes the structure of thebasic aluminum chloride so that water is more readily released, whichthen permits a more ready replacement with glycol. This, in turn,produces a dried solid of lower water content and little or nodecomposition (when basic aluminum chlorides lose water on drying,decomposition occurs resulting in alcohol insolubility and eventuallyeven water I insolubility). As a result, the solubility rate is notsacrificed (spray drying seems to be the primary factor which increasesthe solubility rate) and the compatibility with halocarbons isincreased.

In summation, 'it can be said that refluxing does not have a significanteffect on vacuum dried products except to slightly increasecompatibility. It is a primary advantage of the spray drying process ofthe present invention in that products of lower water content can bemade without the need for excessive quantities of glycol and withminimal decomposition. The low water content and reasonably low glycolcontent in the finished product tend to give higher compatibilities.

The complexes of the present invention have prime utility in aerosolformulations used as antiperspirants. Thus, more concentratedpreparations may be prepared, and anhydrous alcohol may be used. The useof the anhydrous alcohol minimizes corrosion of the aerosol containerand its metal elements.

The compatibility of the complexes of the present invention with theaerosol propellants facilitates the dispensing of the complexes of thepresent invention by means of aerosols. Thus, valve clogging and othermalfunction of the aerosol container and its components is minimized.

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes thereof and,accordingly, reference should be made to the appended claims, ratherthan to the foregoing specification as indicating the scope of theinvention.

It is claimed:

1. The method of preparing an inorganic-organic coordinated complex ofaluminum having relatively high solubility in anhydrous ethanol andcompatibility with aerosol propellants comprising refluxing for betweenabout 2 to 6 hours an aqueous solution of basic aluminum chloride inwhich the atomic ratio of aluminum to chlorine is between 1.88 to 1.95to 1 at a temperature of between about to C., reacting said refluxedbasic aluminum chloride with a polyhydroxy compound, having at least 2carbon atoms, each of which is linked to a hydroxy group, at atemperature of between about 50 to C., and drying said mixture byremoving water therefrom by spray drying at atmospheric pressure toyield a product containing from about 1.0 to about 10* weight percentwater determined by Karl Fischer analysis, said product being saidcomplex.

2. A method in accordance with claim 1 in which the basic aluminumchloride is refluxed for about 4 hours.

3. A method in accordance with claim 1 in which the atomic ratio ofaluminum to chlorine is about 1.9 to 1.

4. A method in accordance with claim 1 in which the polyhydroxy compoundis propylene glycol.

5. A- method in accordance with claim 1 in which the reaction mixture ofbasic aluminum chloride and polyhyd'roxy compound is dried by spraydrying s aid mixture at a temperature of between 80 C. and 320 C.

6. A method in accordance with claim 1 in which the product has a watercontent of from about 4 /2 to 8 weight percent determiend by KarlFischer analysis.

7. A method in accordance with claim 1 in which the resulting producthas the formula:

2( z )o.'7-1.1( )4.9-s.1( )0.9-1.1

(1,2 Propylene -Glycol) 8. A method in accordance with claim 1 in whichthe reaction temperature is between about 80 C. to 110 C.

UNITED STATES PATENTS,

2,466,445 3/ 1949 Landau. 2,823,169 2/1958 Brown et al. 2,872,379 2/1959Neumann et al. 3,359,169 12/1967 Slater et al. 1/1969 Jones et al.

TOBIAS E. LEVOW, Primary Examiner H. M. S. SNEED, Assistant ExaminerU.S. C1. X.R.

